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How to Clean Algae off Tank Glass: Full Guide

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One of the most annoying things I’ve ever had to deal with in my many years of owning aquariums is cleaning algae off of aquarium glass. 

To clean algae off of tank glass, you have several options at your disposal, including using a sponge, an aquarium scraper, an aquarium magnet, or even algae eaters. However, the best course of action is to prevent the algae from building up on the aquarium glass in the first place.

Cleaning algae off of the aquarium glass is actually much easier than you might think, as long as you have the right tools. 

Best Ways to Clean Algae Off Tank Glass

There are a few very simple ways to clean algae off of aquarium tank glass, and I’ll start with my favorite one.

Algae magnet

 1. Using a Sponge

Cleaning algae off of aquarium glass really does not require any kind of special tools. On more than one occasion have I used a regular dishwashing sponge to remove all sorts of algae from the inside of my fish tanks. Just make sure that you are using a fresh and clean dish sponge that has not been used to clean any dishes yet.

It is especially important that there is no soap or other chemicals in the sponge, or else you will cause serious harm to your aquarium plants, fish, and other inhabitants. 

I often use the soft side of the sponge for light buildups, but if the algae is really stuck onto the inside of the aquarium glass, using the abrasive side is always an option.

Just be sure that you don’t remove too much of the water with the sponge, because sponges are quite absorbent. 

Also, keep washing the sponge regularly while performing this task, because you don’t want to keep reintroducing the same algae back into the tank.

If you have a short sponge that requires you to have your hand inside of the tank, don’t move too quickly. You don’t want to disturb the water too much, as this may also cause harm to your plants and fish.

2. Using a Scraper, Squeegee, or Razor Blade

If you have some stuck-on algae that just won’t come off of the glass with a sponge alone, your next best option is to use a specialized aquarium glass scraper or even a regular squeegee, if you don’t have a scraper on hand. 

However, I do recommend going for a specialized aquarium glass scraper, as many of these tools will also have sponges integrated into them.

All you have to do here is use the scraper like you would use a squeegee when drying a window. Just scrape the tool along the aquarium glass and allow all of the algae to collect in one spot. If you are doing this properly, the algae should all fall down into the bottom of the aquarium, beside the glass. 

You can then use an aquarium vacuum like this one to suck up all of the algae that you’ve scraped off of the glass.

That said, aquarium scrapers are not all that abrasive or sharp, which means that severe algae buildups might be too much. If this is the case, using something like a very sharp razor blade, held at a 45-degree angle against the glass, should remove any remaining algae buildup.

3. Using an Aquarium Magnet

Both of the options I’ve discussed above involve sticking your hand inside of the tank. If you don’t want to put your hand inside of the tank, another option you have is to use an aquarium magnet. 

An aquarium magnet is a two-part tool which features a magnetic scrubber or pad that goes on the inside of the tank, and a magnetic handle that goes on the outside of the tank.

The two magnetic pieces hold on to each other through the glass, so when you move the handle, the scrubber on the inside moves along the glass. 

All you have to do is move the handle back and forth along the glass, and the cleaning pad will remove algae and other debris from the inside of the tank glass.

What is very convenient about aquarium magnets is that they come in many different sizes and shapes, and there are also different magnet strengths available. This means that you should easily be able to find an aquarium magnet that works for you.

One tip here is to not bring the magnet within a couple inches of the gravel or sand at the bottom of the tank. If you get any of these coarse or abrasive materials stuck under the cleaning pad, you may scratch the aquarium glass. Also be sure to rinse the pad once you are done, and don’t leave the magnet in the tank.

 4. Using Algae Eaters

Whereas the above approaches were much more labor intensive, this one is much easier, albeit it takes longer as well. If you don’t want to clean any of the algae yourself, introducing some algae eating species into the tank is another option you have.

There are a variety of crustaceans, snails, and fish that are all known for being prolific algae eaters. Exactly which of these algae eaters you get depends on the size and type of tank you have, as well as the other inhabitants you already have. Always be sure to research the compatibility of various aquarium animals before purchasing them.

You don’t want to end up with an unsuitable fish just because it happens to eat some algae. Some of the most common allergy eaters out there include the bristlenose pleco, siamese algae eaters, twig catfish, otocinclus, rosy barbs, flag fish, amano shrimp, nerite snails, and ramshorn snails.

Preventing Algae Buildups

As mentioned in the opening section, preventing algae from blooming in the first place makes life a lot easier on this front. Follow the quick tips I’ve provided below to prevent algae buildups from occurring.

·       Algae really likes phosphate and nitrogen. If you have too many fish in one tank, the water may have elevated nitrogen and phosphate levels, which can cause algae blooms to occur. Therefore, make sure that you don’t overstock your tank.

·       To remove the excess nitrogen, phosphate, and other nutrients that algae requires to grow, having a functioning aquarium filter is essential as well. You need to have all three major types of water filtration, including mechanical, biological, and chemical filtration.

·       Don’t overfeed your fish, because excess fish waste, as well as uneaten food, can both release nutrients and substances into the water that algae can use to grow.

·       Don’t leave your aquarium lights on for more than 10 or 12 hours per day, because algae requires light to grow. The more light you provide your tank with, the more likely algae blooms are to occur.

·       Make sure that you thoroughly sterilize any aquarium plants or decorations before placing them in the tank, as they may contain algae. Find out more about controlling algae in newly established tanks right here! 


As you can see, cleaning algae off of aquarium glass is as easy as using a simple manual tool such as a sponge, scraper, or aquarium magnet. Having algae eaters do some of the work for you is always an option, although the best course of action is always to prevent algae from occurring in the first place.

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